Error when using upper case database names

$ sudo mariadb -u root

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 9

Server version: 10.5.4-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> create database bug1;

Query OK, 1 row affected (0.000 sec)

MariaDB [(none)]> use bug1;

Database changed

MariaDB [bug1]> create table t1(c1 int) engine=columnstore;

Query OK, 0 rows affected (0.208 sec)

MariaDB [bug1]> insert into t1 values(1);

Query OK, 1 row affected (0.075 sec)

MariaDB [bug1]> select * from t1;

+------+

| c1   |

+------+

|    1 |

+------+

1 row in set (0.030 sec)

MariaDB [bug1]> create database BUG2;

Query OK, 1 row affected (0.000 sec)

MariaDB [bug1]> use BUG2;

Database changed

MariaDB [BUG2]> create table t2(c1 int) engine=columnstore;

Query OK, 0 rows affected (0.203 sec)

MariaDB [BUG2]> insert into t2 values(1);

Query OK, 1 row affected (0.079 sec)

MariaDB [BUG2]> select * from t2;

ERROR 1815 (HY000): Internal error: IDB-1000: 't2' and 't2' are not joined.